migrate subdomain redirects to Azure

7 files changed, 259 insertions, 141 deletions

diff --git a/src/SMAPI.Web/Framework/RedirectRules/RedirectHostsToUrlsRule.cs b/src/SMAPI.Web/Framework/RedirectRules/RedirectHostsToUrlsRule.cs
new file mode 100644
index 00000000..d75ee791
--- /dev/null
+++ b/src/SMAPI.Web/Framework/RedirectRules/RedirectHostsToUrlsRule.cs
@@ -0,0 +1,54 @@
+using System;
+using System.Net;
+using Microsoft.AspNetCore.Rewrite;
+
+namespace StardewModdingAPI.Web.Framework.RedirectRules
+{
+    /// <summary>Redirect hostnames to a URL if they match a condition.</summary>
+    internal class RedirectHostsToUrlsRule : RedirectMatchRule
+    {
+        /*********
+        ** Fields
+        *********/
+        /// <summary>Maps a lowercase hostname to the resulting redirect URL.</summary>
+        private readonly Func<string, string> Map;
+
+
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Construct an instance.</summary>
+        /// <param name="statusCode">The status code to use for redirects.</param>
+        /// <param name="map">Hostnames mapped to the resulting redirect URL.</param>
+        public RedirectHostsToUrlsRule(HttpStatusCode statusCode, Func<string, string> map)
+        {
+            this.StatusCode = statusCode;
+            this.Map = map ?? throw new ArgumentNullException(nameof(map));
+        }
+
+
+        /*********
+        ** Private methods
+        *********/
+        /// <summary>Get the new redirect URL.</summary>
+        /// <param name="context">The rewrite context.</param>
+        /// <returns>Returns the redirect URL, or <c>null</c> if the redirect doesn't apply.</returns>
+        protected override string GetNewUrl(RewriteContext context)
+        {
+            // get requested host
+            string host = context.HttpContext.Request.Host.Host;
+            if (host == null)
+                return null;
+
+            // get new host
+            host = this.Map(host);
+            if (host == null)
+                return null;
+
+            // rewrite URL
+            UriBuilder uri = this.GetUrl(context.HttpContext.Request);
+            uri.Host = host;
+            return uri.ToString();
+        }
+    }
+}
diff --git a/src/SMAPI.Web/Framework/RedirectRules/RedirectMatchRule.cs b/src/SMAPI.Web/Framework/RedirectRules/RedirectMatchRule.cs
new file mode 100644
index 00000000..6e81c4ca
--- /dev/null
+++ b/src/SMAPI.Web/Framework/RedirectRules/RedirectMatchRule.cs
@@ -0,0 +1,58 @@
+using System;
+using System.Net;
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Rewrite;
+
+namespace StardewModdingAPI.Web.Framework.RedirectRules
+{
+    /// <summary>Redirect matching requests to a URL.</summary>
+    internal abstract class RedirectMatchRule : IRule
+    {
+        /*********
+        ** Fields
+        *********/
+        /// <summary>The status code to use for redirects.</summary>
+        protected HttpStatusCode StatusCode { get; set; } = HttpStatusCode.Redirect;
+
+
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Applies the rule. Implementations of ApplyRule should set the value for <see cref="RewriteContext.Result" /> (defaults to RuleResult.ContinueRules).</summary>
+        /// <param name="context">The rewrite context.</param>
+        public void ApplyRule(RewriteContext context)
+        {
+            string newUrl = this.GetNewUrl(context);
+            if (newUrl == null)
+                return;
+
+            HttpResponse response = context.HttpContext.Response;
+            response.StatusCode = (int)HttpStatusCode.Redirect;
+            response.Headers["Location"] = newUrl;
+            context.Result = RuleResult.EndResponse;
+        }
+
+
+        /*********
+        ** Protected methods
+        *********/
+        /// <summary>Get the new redirect URL.</summary>
+        /// <param name="context">The rewrite context.</param>
+        /// <returns>Returns the redirect URL, or <c>null</c> if the redirect doesn't apply.</returns>
+        protected abstract string GetNewUrl(RewriteContext context);
+
+        /// <summary>Get the full request URL.</summary>
+        /// <param name="request">The request.</param>
+        protected UriBuilder GetUrl(HttpRequest request)
+        {
+            return new UriBuilder
+            {
+                Scheme = request.Scheme,
+                Host = request.Host.Host,
+                Port = request.Host.Port ?? -1,
+                Path = request.PathBase + request.Path,
+                Query = request.QueryString.Value
+            };
+        }
+    }
+}
diff --git a/src/SMAPI.Web/Framework/RedirectRules/RedirectPathsToUrlsRule.cs b/src/SMAPI.Web/Framework/RedirectRules/RedirectPathsToUrlsRule.cs
new file mode 100644
index 00000000..16397c1e
--- /dev/null
+++ b/src/SMAPI.Web/Framework/RedirectRules/RedirectPathsToUrlsRule.cs
@@ -0,0 +1,54 @@
+using System.Collections.Generic;
+using System.Linq;
+using System.Text.RegularExpressions;
+using Microsoft.AspNetCore.Rewrite;
+
+namespace StardewModdingAPI.Web.Framework.RedirectRules
+{
+    /// <summary>Redirect paths to URLs if they match a condition.</summary>
+    internal class RedirectPathsToUrlsRule : RedirectMatchRule
+    {
+        /*********
+        ** Fields
+        *********/
+        /// <summary>Regex patterns matching the current URL mapped to the resulting redirect URL.</summary>
+        private readonly IDictionary<Regex, string> Map;
+
+
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Construct an instance.</summary>
+        /// <param name="map">Regex patterns matching the current URL mapped to the resulting redirect URL.</param>
+        public RedirectPathsToUrlsRule(IDictionary<string, string> map)
+        {
+            this.Map = map.ToDictionary(
+                p => new Regex(p.Key, RegexOptions.IgnoreCase | RegexOptions.Compiled),
+                p => p.Value
+            );
+        }
+
+
+        /*********
+        ** Protected methods
+        *********/
+        /// <summary>Get the new redirect URL.</summary>
+        /// <param name="context">The rewrite context.</param>
+        /// <returns>Returns the redirect URL, or <c>null</c> if the redirect doesn't apply.</returns>
+        protected override string GetNewUrl(RewriteContext context)
+        {
+            string path = context.HttpContext.Request.Path.Value;
+
+            if (!string.IsNullOrWhiteSpace(path))
+            {
+                foreach ((Regex pattern, string url) in this.Map)
+                {
+                    if (pattern.IsMatch(path))
+                        return pattern.Replace(path, url);
+                }
+            }
+
+            return null;
+        }
+    }
+}
diff --git a/src/SMAPI.Web/Framework/RedirectRules/RedirectToHttpsRule.cs b/src/SMAPI.Web/Framework/RedirectRules/RedirectToHttpsRule.cs
new file mode 100644
index 00000000..2a503ae3
--- /dev/null
+++ b/src/SMAPI.Web/Framework/RedirectRules/RedirectToHttpsRule.cs
@@ -0,0 +1,47 @@
+using System;
+using System.Net;
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Rewrite;
+
+namespace StardewModdingAPI.Web.Framework.RedirectRules
+{
+    /// <summary>Redirect requests to HTTPS.</summary>
+    internal class RedirectToHttpsRule : RedirectMatchRule
+    {
+        /*********
+        ** Fields
+        *********/
+        /// <summary>Matches requests which should be ignored.</summary>
+        private readonly Func<HttpRequest, bool> Except;
+
+
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Construct an instance.</summary>
+        /// <param name="except">Matches requests which should be ignored.</param>
+        public RedirectToHttpsRule(Func<HttpRequest, bool> except = null)
+        {
+            this.Except = except ?? (req => false);
+            this.StatusCode = HttpStatusCode.RedirectKeepVerb;
+        }
+
+
+        /*********
+        ** Protected methods
+        *********/
+        /// <summary>Get the new redirect URL.</summary>
+        /// <param name="context">The rewrite context.</param>
+        /// <returns>Returns the redirect URL, or <c>null</c> if the redirect doesn't apply.</returns>
+        protected override string GetNewUrl(RewriteContext context)
+        {
+            HttpRequest request = context.HttpContext.Request;
+            if (request.IsHttps || this.Except(request))
+                return null;
+
+            UriBuilder uri = this.GetUrl(request);
+            uri.Scheme = "https";
+            return uri.ToString();
+        }
+    }
+}
diff --git a/src/SMAPI.Web/Framework/RewriteRules/ConditionalRedirectToHttpsRule.cs b/src/SMAPI.Web/Framework/RewriteRules/ConditionalRedirectToHttpsRule.cs
deleted file mode 100644
index 36effd82..00000000
--- a/src/SMAPI.Web/Framework/RewriteRules/ConditionalRedirectToHttpsRule.cs
+++ /dev/null
@@ -1,62 +0,0 @@
-using System;
-using System.Net;
-using System.Text;
-using Microsoft.AspNetCore.Http;
-using Microsoft.AspNetCore.Rewrite;
-
-namespace StardewModdingAPI.Web.Framework.RewriteRules
-{
-    /// <summary>Redirect requests to HTTPS.</summary>
-    /// <remarks>Derived from <a href="https://stackoverflow.com/a/44526747/262123" /> and <see cref="Microsoft.AspNetCore.Rewrite.Internal.RedirectToHttpsRule"/>.</remarks>
-    internal class ConditionalRedirectToHttpsRule : IRule
-    {
-        /*********
-        ** Fields
-        *********/
-        /// <summary>A predicate which indicates when the rule should be applied.</summary>
-        private readonly Func<HttpRequest, bool> ShouldRewrite;
-
-
-        /*********
-        ** Public methods
-        *********/
-        /// <summary>Construct an instance.</summary>
-        /// <param name="shouldRewrite">A predicate which indicates when the rule should be applied.</param>
-        public ConditionalRedirectToHttpsRule(Func<HttpRequest, bool> shouldRewrite = null)
-        {
-            this.ShouldRewrite = shouldRewrite ?? (req => true);
-        }
-
-        /// <summary>Applies the rule. Implementations of ApplyRule should set the value for <see cref="RewriteContext.Result" /> (defaults to RuleResult.ContinueRules).</summary>
-        /// <param name="context">The rewrite context.</param>
-        public void ApplyRule(RewriteContext context)
-        {
-            HttpRequest request = context.HttpContext.Request;
-
-            // check condition
-            if (this.IsSecure(request) || !this.ShouldRewrite(request))
-                return;
-
-            // redirect request
-            HttpResponse response = context.HttpContext.Response;
-            response.StatusCode = (int)HttpStatusCode.RedirectKeepVerb;
-            response.Headers["Location"] = new StringBuilder()
-                .Append("https://")
-                .Append(request.Host.Host)
-                .Append(request.PathBase)
-                .Append(request.Path)
-                .Append(request.QueryString)
-                .ToString();
-            context.Result = RuleResult.EndResponse;
-        }
-
-        /// <summary>Get whether the request was received over HTTPS.</summary>
-        /// <param name="request">The request to check.</param>
-        public bool IsSecure(HttpRequest request)
-        {
-            return
-                request.IsHttps // HTTPS to server
-                || string.Equals(request.Headers["x-forwarded-proto"], "HTTPS", StringComparison.OrdinalIgnoreCase); // HTTPS to AWS load balancer
-        }
-    }
-}
diff --git a/src/SMAPI.Web/Framework/RewriteRules/RedirectToUrlRule.cs b/src/SMAPI.Web/Framework/RewriteRules/RedirectToUrlRule.cs
deleted file mode 100644
index ab9e019c..00000000
--- a/src/SMAPI.Web/Framework/RewriteRules/RedirectToUrlRule.cs
+++ /dev/null
@@ -1,57 +0,0 @@
-using System;
-using System.Net;
-using System.Text.RegularExpressions;
-using Microsoft.AspNetCore.Http;
-using Microsoft.AspNetCore.Rewrite;
-
-namespace StardewModdingAPI.Web.Framework.RewriteRules
-{
-    /// <summary>Redirect requests to an external URL if they match a condition.</summary>
-    internal class RedirectToUrlRule : IRule
-    {
-        /*********
-        ** Fields
-        *********/
-        /// <summary>Get the new URL to which to redirect (or <c>null</c> to skip).</summary>
-        private readonly Func<HttpRequest, string> NewUrl;
-
-
-        /*********
-        ** Public methods
-        *********/
-        /// <summary>Construct an instance.</summary>
-        /// <param name="shouldRewrite">A predicate which indicates when the rule should be applied.</param>
-        /// <param name="url">The new URL to which to redirect.</param>
-        public RedirectToUrlRule(Func<HttpRequest, bool> shouldRewrite, string url)
-        {
-            this.NewUrl = req => shouldRewrite(req) ? url : null;
-        }
-
-        /// <summary>Construct an instance.</summary>
-        /// <param name="pathRegex">A case-insensitive regex to match against the path.</param>
-        /// <param name="url">The external URL.</param>
-        public RedirectToUrlRule(string pathRegex, string url)
-        {
-            Regex regex = new Regex(pathRegex, RegexOptions.IgnoreCase | RegexOptions.Compiled);
-            this.NewUrl = req => req.Path.HasValue ? regex.Replace(req.Path.Value, url) : null;
-        }
-
-        /// <summary>Applies the rule. Implementations of ApplyRule should set the value for <see cref="RewriteContext.Result" /> (defaults to RuleResult.ContinueRules).</summary>
-        /// <param name="context">The rewrite context.</param>
-        public void ApplyRule(RewriteContext context)
-        {
-            HttpRequest request = context.HttpContext.Request;
-
-            // check rewrite
-            string newUrl = this.NewUrl(request);
-            if (newUrl == null || newUrl == request.Path.Value)
-                return;
-
-            // redirect request
-            HttpResponse response = context.HttpContext.Response;
-            response.StatusCode = (int)HttpStatusCode.Redirect;
-            response.Headers["Location"] = newUrl;
-            context.Result = RuleResult.EndResponse;
-        }
-    }
-}
diff --git a/src/SMAPI.Web/Startup.cs b/src/SMAPI.Web/Startup.cs
index ddfae166..dee2edc2 100644
--- a/src/SMAPI.Web/Startup.cs
+++ b/src/SMAPI.Web/Startup.cs
@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Net;
 using Hangfire;
 using Hangfire.MemoryStorage;
 using Hangfire.Mongo;
@@ -27,7 +28,7 @@ using StardewModdingAPI.Web.Framework.Clients.Nexus;
 using StardewModdingAPI.Web.Framework.Clients.Pastebin;
 using StardewModdingAPI.Web.Framework.Compression;
 using StardewModdingAPI.Web.Framework.ConfigModels;
-using StardewModdingAPI.Web.Framework.RewriteRules;
+using StardewModdingAPI.Web.Framework.RedirectRules;
 using StardewModdingAPI.Web.Framework.Storage;
 
 namespace StardewModdingAPI.Web
@@ -270,26 +271,49 @@ namespace StardewModdingAPI.Web
         /// <summary>Get the redirect rules to apply.</summary>
         private RewriteOptions GetRedirectRules()
         {
-            var redirects = new RewriteOptions();
-
-            // redirect to HTTPS (except API for Linux/Mac Mono compatibility)
-            redirects.Add(new ConditionalRedirectToHttpsRule(
-                shouldRewrite: req =>
-                    req.Host.Host != "localhost"
-                    && !req.Path.StartsWithSegments("/api")
-            ));
-
-            // shortcut redirects
-            redirects.Add(new RedirectToUrlRule(@"^/3\.0\.?$", "https://stardewvalleywiki.com/Modding:Migrate_to_SMAPI_3.0"));
-            redirects.Add(new RedirectToUrlRule(@"^/(?:buildmsg|package)(?:/?(.*))$", "https://github.com/Pathoschild/SMAPI/blob/develop/docs/technical/mod-package.md#$1")); // buildmsg deprecated, remove when SDV 1.4 is released
-            redirects.Add(new RedirectToUrlRule(@"^/community\.?$", "https://stardewvalleywiki.com/Modding:Community"));
-            redirects.Add(new RedirectToUrlRule(@"^/compat\.?$", "https://smapi.io/mods"));
-            redirects.Add(new RedirectToUrlRule(@"^/docs\.?$", "https://stardewvalleywiki.com/Modding:Index"));
-            redirects.Add(new RedirectToUrlRule(@"^/install\.?$", "https://stardewvalleywiki.com/Modding:Player_Guide/Getting_Started#Install_SMAPI"));
-            redirects.Add(new RedirectToUrlRule(@"^/troubleshoot(.*)$", "https://stardewvalleywiki.com/Modding:Player_Guide/Troubleshooting$1"));
-            redirects.Add(new RedirectToUrlRule(@"^/xnb\.?$", "https://stardewvalleywiki.com/Modding:Using_XNB_mods"));
-
-            // redirect legacy canimod.com URLs
+            var redirects = new RewriteOptions()
+                // shortcut paths
+                .Add(new RedirectPathsToUrlsRule(new Dictionary<string, string>
+                {
+                    [@"^/3\.0\.?$"] = "https://stardewvalleywiki.com/Modding:Migrate_to_SMAPI_3.0",
+                    [@"^/(?:buildmsg|package)(?:/?(.*))$"] = "https://github.com/Pathoschild/SMAPI/blob/develop/docs/technical/mod-package.md#$1", // buildmsg deprecated, remove when SDV 1.4 is released
+                    [@"^/community\.?$"] = "https://stardewvalleywiki.com/Modding:Community",
+                    [@"^/compat\.?$"] = "https://smapi.io/mods",
+                    [@"^/docs\.?$"] = "https://stardewvalleywiki.com/Modding:Index",
+                    [@"^/install\.?$"] = "https://stardewvalleywiki.com/Modding:Player_Guide/Getting_Started#Install_SMAPI",
+                    [@"^/troubleshoot(.*)$"] = "https://stardewvalleywiki.com/Modding:Player_Guide/Troubleshooting$1",
+                    [@"^/xnb\.?$"] = "https://stardewvalleywiki.com/Modding:Using_XNB_mods"
+                }))
+
+                // legacy paths
+                .Add(new RedirectPathsToUrlsRule(this.GetLegacyPathRedirects()))
+
+                // subdomains
+                .Add(new RedirectHostsToUrlsRule(HttpStatusCode.PermanentRedirect, host => host switch
+                {
+                    "api.smapi.io" => "smapi.io/api",
+                    "json.smapi.io" => "smapi.io/json",
+                    "log.smapi.io" => "smapi.io/log",
+                    "mods.smapi.io" => "smapi.io/mods",
+                    _ => host.EndsWith(".smapi.io")
+                        ? "smapi.io"
+                        : null
+                }))
+
+                // redirect to HTTPS (except API for Linux/Mac Mono compatibility)
+                .Add(
+                    new RedirectToHttpsRule(except: req => req.Host.Host == "localhost" || req.Path.StartsWithSegments("/api"))
+                );
+
+            return redirects;
+        }
+
+        /// <summary>Get the redirects for legacy paths that have been moved elsewhere.</summary>
+        private IDictionary<string, string> GetLegacyPathRedirects()
+        {
+            var redirects = new Dictionary<string, string>();
+
+            // canimod.com => wiki
             var wikiRedirects = new Dictionary<string, string[]>
             {
                 ["Modding:Index#Migration_guides"] = new[] { "^/for-devs/updating-a-smapi-mod", "^/guides/updating-a-smapi-mod" },
@@ -306,7 +330,7 @@ namespace StardewModdingAPI.Web
             foreach ((string page, string[] patterns) in wikiRedirects)
             {
                 foreach (string pattern in patterns)
-                    redirects.Add(new RedirectToUrlRule(pattern, "https://stardewvalleywiki.com/" + page));
+                    redirects.Add(pattern, "https://stardewvalleywiki.com/" + page);
             }
 
             return redirects;